1. Field of the Invention
The present invention is directed to a process and apparatus for making crumb and powder rubber from recycled rubber sources. More specifically, the present invention is directed to a process and apparatus for making crumb and powder rubber from a preprocessed source of used rubber particles having a predetermined particle size range.
2. Background of the Prior Art
It is long been known that the disposal of used tires and other rubber articles represents a major environmental problem insofar as used tires overwhelm waste disposal sites and indiscriminate discarding of tires and like rubber articles create major environmental problems. It is for this reason that processes have been developed to dispose of tires in a manner that not only eliminates them as an environmental problem but provides incentives for practice of those tire disposal processes.
These processes originally focused upon tire comminution which recovered the inherent fuel value of the significant combustible content of the vehicle tires. More recently, processes which recover the rubber constituent of vehicle tires, for reuse in the manufacture of rubber-containing articles, have been developed.
Although these processes encouraged environmental protection by providing processes for the utility of rubber in the further manufacturing of new rubber products, a major concern associated with these processes has been the inability to provide purchasers of the rubber products produced in these processes with a rubber material that can be readily incorporated into the purchaser's production feed. That is, randomness of comminution variables and the types and condition of the used vehicle tire feed have produced random rubber products. Probably the most undesirable result of this random production has been the unpredictable rubber product particle size distribution. That is, although a lively market exists for crumb and powder rubber this market has not yet been fully exploited due to the inability to produce crumb and powder rubber in the particle size ranges required by tire and other rubber product producers who are the target purchasers of crumb and powder rubber products.
U.S. Pat. No. 5,588,600 describes a process and apparatus for low temperature comminution of tires in which cryogenic fluids, employed in embrittling the tires so that comminution can effectively occur, is recycled. This process produces crumb rubber of a sufficiently small particle size desirable to tire and other rubber product manufacturers. However, even the process of the '600 patent provides no assurance that the product rubber particle size range is desired by the customer, the manufacturer of new tires and other rubber product goods.
Other disclosures of process and apparatus for reducing rubber to fine particle size include U.S. Pat. Nos. 5,368,240 and 4,863,106. Although both of these disclosures describe processes for producing fine-sized rubber utilizing cryogenic fluids, neither of these references disclose means for custom designing the particle size range of the product to enhance commercial viability of such processing.
The above remarks establish the need in the art for a new apparatus and process which not only consumes used rubber goods, particularly tires, from the environment but, in addition, produces a crumb and powder rubber product that is highly marketable insofar as it is provided in predetermined particle size ranges and in increased quantities desired by manufactures of tires and other rubber products.